The majority of backpacking stoves in existence function by burning some type of highly combustible gas or liquid fuel such as propane, butane, or ethanol. While these types of stoves are light enough for backpacking they do require the user to carry fuel which adds to the pack weight. Fuel availability is also limited to how much fuel the user decides to bring. Stoves that use solid fuel (wood) gathered on site as a fuel liberate the backpacker from the need to carry fuel into the backcountry and guarantee the availability of fuel indefinitely. The use of wood as a fuel however requires a large combustion chamber that makes these types of stoves too large and too heavy for backpacking.
Many designs exist for collapsible stoves of this type. While these designs reduce the pack size of the stove they do not reduce pack weight, in many cases they increase pack weight instead due to various joint connection hardware. Another major drawback of collapsible solid fuel stoves is that the inner surfaces of the combustion chamber that during combustion accumulate heavy deposits of soot often become exposed to outside objects when in a collapsed or disassembled state.
However with a forced inflow of air, sufficient combustion can be achieved in a small enough combustion chamber to allow for a light enough and small enough stove to be used for backpacking without the need for a collapsible combustion chamber. This has been tried in the past using battery powered electric fans that blow air into the combustion chamber. This has eliminated the need to bring fuel but created a need to bring batteries instead, these types of stoves are also at risk of suffering mechanical and electric breakdowns.
Examples of previous patents of designs of wood burning campstoves are listed below. The present invention presents a backpacking stove with a small enough combustion chamber to be used for backpacking and a completely human powered air intake system with no electric components.
Prior Art:
U.S. Pat. No. 5,915,371 to Hering (1999) discloses a cylindrical collapsible stove powered by solid fuel. This stove is based on the flue effect but does not have a forced inflow of air. By being made of two halves that come apart for small size during transportation it exposes the soot covered inner walls of the combustion chamber to other objects.
U.S. Pat. No. 5,842,463 to Hall (1998) discloses a stove with an outer and inner wall, air is heated between the two walls by thermal conduction before entering the combustion chamber inside the inner wall, the preheated air then allows for a more complete combustion. While this concept raises the efficiency enough to allow for a small combustion chamber it adds another shell and thereby increases the weight of the stove.
U.S. Pat. No. 1,298,762 to Milligan (1919) discloses a basic cylindrical solid fuel stove based on the flue effect. The lack of a combustion enhancing system necessitates a large combustion chamber.
U.S. Pat. No. 3,868,943 to Hottenroth et al. (1975) discloses a solid fuel stove with a forced air inflow by means of a battery powered electric fan blower. While this concept allows for a small combustion chamber it requires a battery-motor-fan assembly that adds weight to the stove. This type of stove is also subject to electromechanical malfunctions and depleted batteries leaving the stove non-operational.
World Pat. No. WO 9937955 to Kunzi (1999) discloses a foldable cooking stove composed of flat metal sheets that fold into a metal box that acts as a combustor. The folding method of this stove is such that no sooted surfaces come in contact with other surfaces or objects thereby eliminating the problem of soot contamination. The need for a large combustion chamber however remains.
The portable solid-fuel camp-stove described herein is small enough and light enough to be used for backpacking. It is powered by small pieces of wood that can be gathered around a campsite. Solid fuel stoves generally require a large combustion chamber, a preheating chamber, or an electromechanical fan system, all of which add significant weight and make these stoves too heavy for backpacking, to provide sufficient power output for cooking. The present invention has a user powered blow-hose air input that allows for sufficient combustion in a small enough combustion chamber to allow for the low weight required for backpacking.